PHYSIOLOGICAL BOTANY. 203 



We shall allow Gaudichaud to continue. 



" According to the old theories, the vascular system of 

 the second individual is formed by a division of the 

 vessels of the first. Hence the vascular system of the 

 second individual is composed of a portion of that of the 

 first. But if the vascular organization of the second in- 

 dividual is more compound than that of the first, the 

 vascular system of the second cannot be formed from 

 the vascular system of the first. If it be granted that all 

 the vessels of the embryo pass into the primordial leaf, 

 the latter should always possess the organization of the 

 embryo only. But this theory is, I think, now properly 

 rejected. According to the theory propounded to you 

 on the 12th of July (by Mirbel), the vessels of the primor- 

 dial leaf must emanate from the inner periphery of the 

 embryo. We are here met by the same difficulties. In 

 fact, what becomes of this theory, when it is proved to 

 you by a large number of facts that, as a rule, the primor- 

 dial leaf is more highly organized than the embryonal 

 leaf, and that e. g. the fourth and fifth leaf almost always 

 contain more vessels than the three or four first leaves ; 

 moreover, when we show by the same facts, not only that 

 the cotyledonary leaf does not send vessels to the pri- 

 mordial leaf, but also, that in many cases it does not 

 receive any from above, and it then has only an ephemeral 

 existence. In this case the first leaf ceases to exist, be- 

 cause it is not strengthened, and to a certain extent 

 vitalised by the second leaf. Is not this an evident proof 

 of the individual vitality of the phyton?" 



Mirbel maintains, if I am correct, that all the vessels 

 of a Palm-stem are not only derived from the internal 

 periphery of the embryo, but also, that wherever leaves 

 arise, new vessels are developed, and thus that they appear 

 at the rings, internally, at the periphery of the stems. 

 From observations which I have made upon this point, I 

 believe that Mirbel is incorrect ; 1 do not find bundles of 

 woody or vascular tissue arising from the rings within 

 the stem, but they all appear to arise from the base of 



